First Oiler with Fluorescent Lighting
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WHAT is believed to be Britain's first vV oil-engined bus to be equipped with fluorescent lighting has been put into service by Nottingham Corporation in connection with the municipal transport golden jubilee. The vehicle is an A.E.C. double-decker.
Current for lighting is derived from a normal 24-volt vehicle battery through a small C.A.V. high-speed rotary converter having an output of about 400 watts at 400 cycles per second, threephase, 100 volts. The converter runs at 8,000 r.p.m., and weighs only 13 lb.
A self-contained fan draws cooling air through an entry at the end of the motor and expels it over the slip rings. The converter is only 9 ins, long and is a single-armature double-wound unit
with a common six-pole field system. The unit is suspended in rubber in a
sound-proofing container, which measures 15 ins, long and II ins, in diameter. The gear is mounted under the off-side rear seats near the wheelarch.
The complete power unit, with silencing arrangements, weighs 30 lb. Plug and socket connectors are used.
Twenty-three specially designed G.E.C. fluorescent fittings are employed, each totally enclosed by a reeded Perspex diffusing cover with opal ends, and carrying an Osram 15-watt warmwhite lamp.
The auxiliary gear is fixed behind each fitting, and in the lower saloon is accommodated between the lining and the outer shell of the bus; on the upper deck, pattresses provide the necessary depth.
The circuit permits almost instant starting and practically constant light output. The average illumination is said to be more than 12 lumens per sq. ft., which is stated to be over twice that normally obtained in an up-to-date bus installation using tungsten-filament lamps.
The C.A.V. switchboard contains a solenoid-operated switch for connecting the motor to the battery, and a thermal delay switch which is arranged to allow the machine to run up to its normal frequency before connecting the A.C. output to the lamp circuits.